1. Field of the Invention
The invention relates to an optical apparatus and a light source adjusting method thereof. Particularly, the invention relates to a projection apparatus and a light source adjusting method thereof.
2. Description of Related Art
A projection apparatus is a display apparatus used for producing large size images. An imaging principle of the projection apparatus is to convert an illumination beam generated by a light source into an image beam through a light valve, and then project the image beam onto a screen through a lens to form an image. With development of the projection technique and reduction of a fabrication cost, utilization of the projection apparatus is gradually developed from commercial use to domestic use.
In detail, when the projection apparatus functions, an optical path from the light source to an imaging device has to be correct such that a lighting area on the imaging device generated when a light beam is projected thereon is overlapped to the image device, and the image of the imaging device can be completely projected onto the screen through a lens module. If positioning of the light source has an error, problems of brightness reduction and poor imaging quality are encountered. Even if the light source is precisely positioned during assembling, a lampwick of a lamp bulb is still gradually deviated from an original center position as utilization time thereof increases, which results in a fact that a projected image is darkened. In a typical projection apparatus, there is no adjustment mechanism for an illumination system, and the light source is generally fixed in the optical engine, which is locked and fixed after assembling and cannot be adjusted, so that optical quality thereof cannot be optimised.
Taiwan Patent No. 1267606 discloses a mechanism of assembling a light source to a lamp base through screws and a spring. Taiwan Patent No. 579452 discloses a projection apparatus, in which a digital micro mirror device (DMD) can reflect light to a light sensor to control a light flux of the light source. Taiwan utility model patent No. 582494 discloses a device used for adjusting a projection angle and a focal length of a light source. Taiwan Publication No. 200702891 discloses a projection apparatus, in which electricity of a corresponding power is applied on a lamp bulb according to a utilization time corresponding to predetermined gain power data, so as to maintain the lamp bulb to a fixed brightness. U.S. Pat. No. 6,909,560 discloses an adjustment mechanism for a lens of a projection apparatus, by which the lens is adjusted through components such as a gear, a worm and a cam, etc.